This invention relates to rechargeable zinc ion batteries with high capacity.
The high capacity batteries are vital for our modern lives. The annual worldwide market of batteries is over 100 billion dollars and prospers the boost of related industries, for example, consumer electronics, electric vehicles, and communications etc. Development of high capacity battery could push the related industries forward.
The recent U.S. patent (U.S. Pat. No. 8,663,844 B2) invented a so-called zinc ion battery, which uses α-MnO2 as cathode, zinc as anode and ZnSO4 aqueous solution as the electrolyte. The battery chemistry of zinc ion battery is written as:Cathodic reaction:xZn2++2xe−+2xMnO2ZnxMnO2  (1)Anodic reaction:ZnZn2++2e−  (2)
The advantage of zinc ion battery is ecofriendly, safety and low cost. However, the disadvantage of zinc ion battery is the low capacity of the battery. The capacity of MnO2 is as low as 200 mAh g−1, which preclude it from various applications for example electric vehicles. Therefore, it is necessary to discover new cathode active materials with a high capacity to further improve the energy density of zinc ion battery.